Emotion is a complex entity which can be modelled in different ways. When defined as a motor response to stimuli, it can be viewed as belonging to a discrete set; whereas when considered as a subjective feeling, it can be expressed as a continuous vector in multiple dimensions [1]}. Though these two definitions of emotion appear to be different, they have shared and complementary information. Psychological models like Plutchik's wheel of emotions [2]} or Russell's “arousal-valence” space [3]} represent discrete emotions on and within a circle on a continuous “arousal-valence” plane, demonstrating that the values of “arousal” and “valence” are correlated to the perception of discrete emotion.
